Playback devices for audio/video (AV) data, usually based on hard-disk drives (HDD) or optical discs, may have different possibilities to access additional data, e.g. Internet access, Universal Serial Bus (USB) interface etc. for downloading additional contents.
Some high-end TV sets provide the possibility to view two or more programs simultaneously by using picture-in-picture (PIP) technique, which however uses different proprietary technical solutions. The way such a TV set presents different video sequences on the same screen is not flexible, but immediately fixed after manufacturing the TV set.
Available PIP techniques work without any help information extracted from the AV content.